For millennia, what today is known to be theSolar System was regarded as the contents of the "whole universe", so advances in the knowledge of both mostly paralleled. Clear distinction was not made until circa mid-17th century. SeeTimeline of Solar System astronomy for further details on this side.
6th century BCE – TheBabylonian Map of the World shows the Earth surrounded by the cosmic ocean, with seven islands arranged around it so as to form a seven-pointed star. ContemporaryBiblical cosmology reflects the same view of a flat, circular Earth swimming on water and overarched by the solid vault of thefirmament to which are fastened the stars.
6th–4th century BCE – Greek philosophers, as early asAnaximander,[2] introduce the idea of multiple or even infinite universes.[3]Democritus further detailed that these worlds varied in distance, size; the presence, number and size of their suns and moons; and that they are subject to destructive collisions.[4] Also during this time period, the Greeks established that the Earth is spherical rather than flat.[5][6]
6th century BCE –Anaximander conceives a mechanical, non-mythological model of the world: the Earth floats very still in the centre of the infinite, not supported by anything.[7] Its curious shape is that of a cylinder[8] with a height one-third of its diameter. The flat top forms the inhabited world, which is surrounded by a circular oceanic mass. Anaximander considered the Sun as a huge object (larger than the land ofPeloponnesus[9]), and consequently, he realized how far from Earth it might be. In his system the celestial bodies turned at different distances. At the origin, after the separation of hot and cold, a ball of flame appeared that surrounded Earth like bark on a tree. This ball broke apart to form the rest of the Universe. It resembled a system of hollow concentric wheels, filled with fire, with the rims pierced by holes like those of a flute. Consequently, the Sun was the fire that one could see through a hole the same size as the Earth on the farthest wheel, and an eclipse corresponded with theocclusion of that hole. The diameter of the solar wheel was twenty-seven times that of the Earth (or twenty-eight, depending on the sources)[10] and the lunar wheel, whose fire was less intense, eighteen (or nineteen) times. Its hole could change shape, thus explaininglunar phases. The stars and the planets, located closer,[11] followed the same model.[12]
5th century BCE –Pythagoreans such asPhilolaus believed themotion of planets is caused by an out-of-sight "fire" at the centre of the universe (not the Sun) that powers them, and Sun and Earth orbit thatCentral Fire at different distances. The Earth's inhabited side is always opposite to the Central Fire, rendering it invisible to people. They also claimed that the Moon and the planets orbit the Earth.[14] This model depicts a moving Earth, simultaneously self-rotating and orbiting around an external point (but not around the Sun), thus not being geocentrical, contrary to commonintuition. Due to philosophical concerns about the number 10 (a "perfect number" for the Pythagorians), they also added a tenth "hidden body" orCounter-Earth (Antichthon), always in the opposite side of the invisible Central Fire and therefore also invisible from Earth.[15]
4th century BCE –Plato claimed in hisTimaeus thatcircles and spheres are the preferred shape of the universe, thatthe Earth is at the center and is circled by, ordered in-to-outwards: Moon, Sun, Venus, Mercury, Mars, Jupiter, Saturn, and finally thefixed stars located on thecelestial sphere.[16] In Plato's complexcosmogony,[17] thedemiurge gave the primacy to the motion of Sameness and left it undivided; but he divided the motion of Difference in six parts, to have seven unequal circles. He prescribed these circles to move in opposite directions, three of them with equal speeds, the others with unequal speeds, but always in proportion. These circles are the orbits of the heavenly bodies: the three moving at equal speeds are the Sun, Venus and Mercury, while the four moving at unequal speeds are the Moon, Mars, Jupiter and Saturn.[18][19] The complicated pattern of these movements is bound to be repeated again after a period called a 'complete' or'perfect' year.[20] However, others likePhilolaus and Hicetas had rejected geocentrism.[21]
4th century BCE –Eudoxus of Cnidus devised a geometric-mathematical model for the movements of the planets, the first known effort in this sense, based on (conceptual)concentric spheres centered on Earth.[22] To explain thecomplexity of the movements of the planets along with that of the Sun and the Moon, Eudoxus thought they move as if they were attached to a number ofconcentrical, invisible spheres, every of them rotating around its own and different axis and at different paces. His model had twenty-seven homocentric spheres with each sphere explaining a type of observable motion for each celestial object. Eudoxus emphasised that this is a purely mathematical construct of the model in the sense that the spheres of each celestial body do not exist, it just shows the possible positions of the bodies.[23] His model was later refined and expanded byCallippus.
4th century BCE –Aristotle follows the Plato'sEarth-centered universe in which the Earth is stationary and thecosmos (or universe) is finite in extent but infinite in time. He argued for a spherical Earth usinglunar eclipses[24] and other observations. Aristotle adopted and expanded even more the previous Eudoxus' and Callippus' model, but by supposing the spheres were material and crystalline.[25] Aristotle also tried to determine whether the Earth moves and concluded that all the celestial bodies fall towards Earth by natural tendency and since Earth is the centre of that tendency, it is stationary.[26] Plato seems to have obscurely argued that the universe did have a beginning, but Aristotle and others interpreted his words differently.[27]
4th century BCE –De Mundo –Five elements, situated in spheres in five regions, the less being in each case surrounded by the greater – namely, earth surrounded by water, water by air, air by fire, and fire byaether – make up the whole Universe.[28]
4th century BCE –Heraclides Ponticus is said to be the first Greek who proposes that theEarth rotates on its axis, from west to east, once every 24 hours, contradicting Aristotle's teachings.Simplicius says that Heraclides proposed that the irregular movements of the planets can be explained if the Earth moves while the Sun stays still,[29] but these statements are disputed.[30]
3rd century BCE –Archimedes in his essayThe Sand Reckoner, estimates the diameter of the cosmos to be the equivalent instadia of what would in modern times be called twolight years, if Aristarchus' theories were correct.
2nd century BCE –Seleucus of Seleucia elaborates on Aristarchus' heliocentric universe, using the phenomenon oftides to explain heliocentrism. Seleucus was the first to prove the heliocentric system through reasoning. Seleucus' arguments for a heliocentric cosmology were probably related to the phenomenon of tides. According to Strabo (1.1.9), Seleucus was the first to state that the tides are due to the attraction of the Moon, and that the height of the tides depends on the Moon's position relative to the Sun. Alternatively, he may have proved heliocentricity by determining the constants of a geometric model for it.[32]
2nd century BCE –Apollonius of Perga shows the equivalence of two descriptions of theapparent retrograde planet motions (assuming the geocentric model), one using eccentrics and anotherdeferent and epicycles.[33] The latter will be a key feature for future models. The epicycle is described as a small orbit within a greater one, called thedeferent: as a planet orbits the Earth, it also orbits the original orbit, so its trajectory resembles a curve known as anepitrochoid. This could explain how the planet seems to move as viewed from Earth.
2nd century BCE –Eratosthenes determines that the radius of the Earth is roughly 6,400 km.[34]
2nd century BCE –Hipparchus usesparallax to determine that the distance to the Moon is roughly 380,000 km.[35] The work of Hipparchus about the Earth-Moon system was so accurate that he could forecast solar and lunar eclipses for the next six centuries. Also, he discovers theprecession of theequinoxes, and compiles astar catalog of about 850 entries.[36]
c.2nd century BCE–3rd century CE – InHindu cosmology, theManusmriti (1.67–80) andPuranas describe time as cyclical, with a newuniverse (planets and life) created byBrahma every 8.64 billion years. The universe is created, maintained, and destroyed within akalpa (day ofBrahma) period lasting for 4.32 billion years, and is followed by apralaya (night) period of partial dissolution equal in duration. In some Puranas (e.g.Bhagavata Purana), a larger cycle of time is described where matter (mahat-tattva oruniversal womb) is created from primal matter (prakriti) and root matter (pradhana) every 622.08 trillion years, from whichBrahma is born.[37] The elements of the universe are created, used by Brahma, and fully dissolved within amaha-kalpa (life ofBrahma; 100 of his 360-day years) period lasting for 311.04 trillion years containing 36,000kalpas (days) andpralayas (nights), and is followed by amaha-pralaya period of full dissolution equal in duration.[38][39][40][41] The texts also speak of innumerable worlds or universes.[42]
2nd century CE –Ptolemy proposes an Earth-centered universe, with theSun, Moon, and visible planets revolving around the Earth. Based on Apollonius' epicycles,[43] he calculates the positions,orbits and positional equations of theHeavenly bodies along with instruments to measure these quantities. Ptolemy emphasised that the epicycle motion does not apply to the Sun. His main contribution to the model was theequant points. He also re-arranged the heavenly spheres in a different order than Plato did (from Earth outward): Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn and fixed stars, following a long astrological tradition and the decreasing orbital periods. His bookThe Almagest, which also cataloged 1,022stars and otherastronomical objects (largely based upon Hipparchus'), remained the most authoritative text on astronomy and largest astronomical catalogue until the 17th century.[44][45]
2nd century CE-5th century CE – Jain cosmology considers the loka, oruniverse, as an uncreated entity, existing since infinity, the shape of the universe as similar to a man standing with legs apart and arm resting on his waist. This Universe, according toJainism, is broad at the top, narrow at the middle and once again becomes broad at the bottom.
5th century (or earlier) – Buddhist texts speak of "hundreds of thousands of billions, countlessly, innumerably, boundlessly, incomparably, incalculably, unspeakably, inconceivably, immeasurably, inexplicably many worlds" to the east, and "infinite worlds in the ten directions".[46][47]
5th centuryAryabhata writes a treatise on motion of planets,Sun andMoon and stars. Aryabhatta puts forward the theory of rotation of the Earth in its own axis and explainedday and night was caused by the diurnal rotation of theEarth. He models a geocentric universe with the sun, moon, and planets following circular and eccentric orbits with epicycles.[48]
5th century – The Jewishtalmud gives an argument for finite universe theory along with explanation.
Naboth's representation of Martianus Capella's geo-heliocentric astronomical model (1573)
5th century –Martianus Capella describes a modified geocentric model, in which the Earth is at rest in the center of the universe and circled by the Moon, the Sun, three planets and the stars, while Mercury and Venus circle the Sun, all surrounded by the sphere of fixed stars.[49]
6th century –John Philoponus proposes a universe that is finite intime and argues against the ancient Greek notion of an infinite universe
7th century – TheQuran says in Chapter 21: Verse 30 – "Have those who disbelieved not considered that the Heavens and the Earth were a joined entity, and We separated them".
9th–12th centuries –Al-Kindi (Alkindus),Saadia Gaon (Saadia ben Joseph) andAl-Ghazali (Algazel) support a universe that has a finite past and develop two logical arguments for the notion.
12th century –Fakhr al-Din al-Razi discussesIslamic cosmology, rejects Aristotle's idea of an Earth-centered universe, and, in the context of his commentary on theQuranic verse, "All praise belongs to God, Lord of the Worlds," and proposes that the universe has more than "a thousand worlds beyond this world."[50]
12th century –Robert Grosseteste described the birth of the Universe in an explosion and the crystallisation of matter. He also put forward several new ideas such as rotation of the Earth around itsaxis and the cause of day and night. His treatiseDe Luce is the first attempt to describe the heavens and Earth using a single set of physical laws.[51]
14th century –Jewish astronomerLevi ben Gershon (Gersonides) estimates the distance to the outermost orb of the fixed stars to be no less than 159,651,513,380,944Earth radii, or about 100,000light-years in modern units.[52]
15th century –Nicholas of Cusa proposes that the Earth rotates on its axis in his book,On Learned Ignorance (1440).[55] Like Oresme, he also wrote about the possibility of the plurality of worlds.[56]
1584 –Giordano Bruno proposes a non-hierarchical cosmology, wherein the CopernicanSolar System is not the center of the universe, but rather, a relatively insignificantstar system, amongst an infinite multitude of others.[60]
1588 – Tycho Brahe publishes his ownTychonic system, a blend between Ptolemy's classical geocentric model and Copernicus' heliocentric model, in which the Sun and the Moon revolve around the Earth, in the center of universe, and all other planets revolve around the Sun.[61] It is a geo-heliocentric model similar to that described by Somayaji.
1609 –Galileo Galilei examines the skies and constellations through atelescope and concluded that the "fixed stars" which had been studied and mapped were only a tiny portion of the massive universe that lay beyond the reach of the naked eye.[63] When in 1610 he aimed his telescope to the faint strip of theMilky Way, he found it resolves into countless white star-like spots, presumably farther stars themselves.[64]
1610 –Johannes Kepler uses the dark night sky to argue for a finite universe. Shortly after, it was proved by Kepler himself that theJupiter's moons move around the planet the same way planets orbit the Sun, thus makingKepler's laws universal.[65]
1659 –Christiaan Huygens makes precise measurements of the angular distance between the Sun and Venus, which were based on the first absolute measurements of theAstronomical unit.[66]
1687 –Isaac Newton'slaws describe large-scale motion throughout the universe. Theuniversal force of gravity suggested that stars could not simply be fixed or at rest, as their gravitational pulls cause "mutual attraction" and therefore cause them to move in relation to each other.[69]
1704 –John Locke enters the term "Solar System" in the English language, when he used it to refer to the Sun, planets, and comets as a whole.[70] By then it had been stablished beyond doubt that planets are other worlds, and stars are other distant suns, so the whole Solar System is actually only a small part of an immensely large universe, and definitively something distinct.
1720 – Edmund Halley puts forth an early form ofOlbers' paradox (if the universe is infinite, every line of sight would end at a star, thus the night sky would be entirely bright).
1729 –James Bradley discovers theaberration of light, which proved the Earth's motion around the Sun,[72] and also provides a more accurate method to compute thespeed of light closer to its actual value of about 300,000 km/s.
1832–1838 – Following over 100 years of unsuccessful attempts,Thomas Henderson,[76]Friedrich Bessel,[77] andOtto Struve measure theparallax of a few nearby stars; these are the first measurements of any distances outside the Solar System.
One of Andrew Ainslie Common's 1883 photographs of theOrion Nebula, the first to show that a long exposure could record stars and nebulae invisible to the human eye.
1848 –Edgar Allan Poe offers first correct solution to Olbers' paradox inEureka: A Prose Poem, an essay that also suggests the expansion and collapse of the universe.
1862 – By analysing thespectroscopic signature of the Sun and comparing it to those of other stars, FatherAngelo Secchi determines that the Sun in itself is also a star.[80]
1897 –William Thomson, 1st Baron Kelvin, based on the thermal radiation rate and thegravitational contraction forces, argues the age of the Sun to be no more than 20 million years – unless some energy source beyond what was then known was found.[83]
The earliest known photograph of the GreatAndromeda "Nebula" (withM110 to upper left), byIsaac Roberts, 1899.
1904 –Ernest Rutherford argues, in a lecture attended by Kelvin, thatradioactive decay releases heat, providing the unknown energy source Kelvin had suggested, and ultimately leading toradiometric dating of rocks which reveals ages of billions of years for the Solar System bodies, hence the Sun and all the stars.[84]
1912 –Henrietta Leavitt discovers the period-luminosity law forCepheid variable stars, which becomes a crucial step in measuring distances to other galaxies.
1923 –Edwin Hubble measures distances to a few nearby spiral nebulae (galaxies), theAndromeda Galaxy (M31),Triangulum Galaxy (M33), andNGC 6822. The distances place them far outside the Milky Way, and implies that fainter galaxies are much more distant, and the universe is composed of many thousands of galaxies.
1927 –Georges Lemaître discusses the creation event of an expanding universe governed by the Einstein field equations. From its solutions to the Einstein equations, he predicts the distance-redshift relation.
1928 –Howard P. Robertson briefly mentions that Vesto Slipher's redshift measurements combined with brightness measurements of the same galaxies indicate a redshift-distance relation.
1933 –Fritz Zwicky shows that theComa Cluster of galaxies contains large amounts of dark matter. This result agrees with modern measurements, but is generally ignored until the 1970s.
1938 –Paul Dirac suggests thelarge numbers hypothesis, that the gravitational constant may be small because it is decreasing slowly with time.
1948 –Ralph Alpher, Hans Bethe ("in absentia"), andGeorge Gamow examine element synthesis in a rapidly expanding and cooling universe, and suggest that the elements were produced by rapidneutron capture.
1950 –Fred Hoyle coins the term "Big Bang", saying that it was not derisive; it was just a striking image meant to highlight the difference between that and the Steady-State model.
1961 –Robert Dicke argues thatcarbon-basedlife can only arise when the gravitational force is small, because this is when burning stars exist; first use of the weakanthropic principle.
1963 –Maarten Schmidt discovers the firstquasar; these soon provide a probe of the universe back to substantial redshifts.
1968 –Brandon Carter speculates that perhaps the fundamental constants of nature must lie within a restricted range to allow the emergence of life; first use of the strong anthropic principle.
1977 –Gary Steigman,David Schramm, andJames Gunn examine the relation between the primordial helium abundance and number of neutrinos and claim that at most fivelepton families can exist.
1980 –Alan Guth and Alexei Starobinsky independently propose theinflationary Big Bang universe as a possible solution to the horizon and flatness problems.
1981 –Viatcheslav Mukhanov and G. Chibisov propose that quantum fluctuations could lead to large scale structure in aninflationary universe.
1982 – The first CfA galaxy redshift survey is completed.
1982 – Several groups includingJames Peebles, J. Richard Bond and George Blumenthal propose that the universe is dominated by colddark matter.
1983–1987 – The first large computer simulations of cosmic structure formation are run by Davis, Efstathiou, Frenk and White. The results show that cold dark matter produces a reasonable match to observations, but hot dark matter does not.
1990 – Preliminary results fromNASA'sCOBE mission confirm thecosmic microwave background radiation has ablackbody spectrum to an astonishing one part in 105 precision, thus eliminating the possibility of an integrated starlight model proposed for the background by steady state enthusiasts.
1992 – FurtherCOBE measurements discover the very smallanisotropy of thecosmic microwave background, providing a "baby picture" of the seeds of large-scale structure when the universe was around 1/1100th of its present size and 380,000 years old.
1995 – The first planet around a Sun-like star is discovered, in orbit around the star51 Pegasi.[99]
1996 – The firstHubble Deep Field is released, providing a clear view of very distant galaxies when the universe was around one-third of its present age.
1998 – Controversial evidence for thefine-structure constant varying over the lifetime of the universe is first published.
1999 – Measurements of thecosmic microwave background radiation with finer resolution than COBE, (most notably by theBOOMERanG experiment see Mauskopf et al., 1999, Melchiorri et al., 1999, de Bernardis et al. 2000) provide evidence for oscillations (the first acoustic peak) in theanisotropy angular spectrum, as expected in the standard model of cosmological structure formation. The angular position of this peak indicates that the geometry of the universe is close to flat.
2001 – The2dF Galaxy Redshift Survey (2dF) by an Australian/British team gave strong evidence that the matter density is near 25% of critical density. Together with the CMB results for a flat universe, this provides independent evidence for acosmological constant or similardark energy.
2002 – TheCosmic Background Imager (CBI) inChile obtained images of the cosmic microwave background radiation with the highest angular resolution of 4 arc minutes. It also obtained the anisotropy spectrum at high-resolution not covered before up to l ~ 3000. It found a slight excess in power at high-resolution (l > 2500) not yet completely explained, the so-called "CBI-excess".
2003 – NASA'sWilkinson Microwave Anisotropy Probe (WMAP) obtained full-sky detailed pictures of the cosmic microwave background radiation. The images can be interpreted to indicate that the universe is 13.7 billion years old (within one percent error), and are very consistent with theLambda-CDM model and the density fluctuations predicted byinflation.
2006–2011 – Improved measurements fromWMAP, new supernova surveys ESSENCE and SNLS, and baryon acoustic oscillations fromSDSS andWiggleZ, continue to be consistent with the standardLambda-CDM model.
2020 – PhysicistLucas Lombriser of theUniversity of Geneva presents a possible way of reconciling the two significantly different determinations of theHubble constant by proposing the notion of a surroundingvast "bubble", 250 million light years in diameter, that is half the density of the rest of the universe.[117][118]
^"there are innumerable worlds of different sizes. In some there is neither sun nor moon, in others they are larger than in ours and others have more than one. These worlds are at irregular distances, more in one direction and less in another, and some are flourishing, others declining. Here they come into being, there they die, and they are destroyed by collision with one another. Some of the worlds have no animal or vegetable life nor any water."
^Most of Anaximander's model of the Universe comes from pseudo-Plutarch (II, 20–28):
"[The Sun] is a circle twenty-eight times as big as the Earth, with the outline similar to that of a fire-filled chariot wheel, on which appears a mouth in certain places and through which it exposes its fire, as through the hole on a flute. [...] the Sun is equal to the Earth, but the circle on which it breathes and on which it's borne is twenty-seven times as big as the whole earth. [...] [The eclipse] is when the mouth from which comes the fire heat is closed. [...] [The Moon] is a circle nineteen times as big as the whole earth, all filled with fire, like that of the Sun".
^Thurston, Hugh (1994).Early astronomy. New York: Springer-Verlag New York. p. 111.ISBN0-387-94107-X.
^Dreyer, John Louis Emil (1906).History of the planetary systems from Thales to Kepler. p. 42.To complete the number ten, Philolaus created the antichthon, or counter-earth. This tenth planet is always invisible to us, because it is between us and the central fire and always keeps pace with the Earth.
^Pedersen, Olaf (1993).Early physics and astronomy. A historical introduction. Cambridge (UK): Cambridge University Press.ISBN0-521-40340-5.
^"The components from which he made the soul and the way in which he made it were as follows: In between theBeing that is indivisible and always changeless, and the one that is divisible and comes to be in the corporeal realm, he mixed a third, intermediate form of being, derived from the other two. Similarly, he made a mixture of theSame, and then one of theDifferent, in between their indivisible and their corporeal, divisible counterparts. And he took the three mixtures and mixed them together to make a uniform mixture, forcing the Different, which was hard to mix, into conformity with the Same. Now when he had mixed these two with Being, and from the three had made a single mixture, he redivided the whole mixture into as many parts as his task required, each part remaining a mixture of the Same, the Different and Being." (35a-b), translation Donald J. Zeyl
^Aristotle; Forster, E. S. (Edward Seymour); Dobson, J. F. (John Frederic) (1914).De Mundo. Oxford: The Clarendon Press. p. 2.{{cite book}}: CS1 maint: multiple names: authors list (link)
^G. J. Toomer, "Hipparchus on the distances of the sun and moon," Archive for History of Exact Sciences14 (1974), 126–142.
^Alexander Jones "Ptolemy in Perspective: Use and Criticism of his Work from Antiquity to the Nineteenth Century, Springer, 2010, p.36.
^"Mahattattva, Mahat-tattva: 5 definitions".Wisdom Library. February 10, 2021.Mahattattva (महत्तत्त्व) or simply Mahat refers to a primordial principle of the nature of both pradhāna and puruṣa, according to the 10th century Saurapurāṇa: one of the various Upapurāṇas depicting Śaivism.—[...] From the disturbed prakṛti and the puruṣa sprang up the seed of mahat, which is of the nature of both pradhāna and puruṣa. The mahattattva is then covered by the pradhāna and being so covered it differentiates itself as the sāttvika, rājasa and tāmasa-mahat. The pradhāna covers the mahat just as a seed is covered by the skin. Being so covered there spring from the three fold mahat the threefold ahaṃkāra called vaikārika, taijasa and bhūtādi or tāmasa.
^Ansari, S.M.R. (March 1977). "Aryabhata I, His Life and His Contributions".Bulletin of the Astronomical Society of India.5 (1):10–18.Bibcode:1977BASI....5...10A.hdl:2248/502.
^Bruce S. Eastwood,Ordering the Heavens: Roman Astronomy and Cosmology in the Carolingian Renaissance (Leiden: Brill, 2007), pp. 238-9.
^Lewis, Neil (2021),"Robert Grosseteste", in Zalta, Edward N. (ed.),The Stanford Encyclopedia of Philosophy (Fall 2021 ed.), Metaphysics Research Lab, Stanford University, retrieved2022-11-05
^Kirschner, Stefan (2021),"Nicole Oresme", in Zalta, Edward N. (ed.),The Stanford Encyclopedia of Philosophy (Fall 2021 ed.), Metaphysics Research Lab, Stanford University, retrieved2022-11-09
^Hellyer, Marcus, ed. (2008).The Scientific Revolution: The Essential Readings. Blackwell Essential Readings in History. Vol. 7.John Wiley & Sons. p. 63.ISBN978-0-470-75477-1.The Puritan Thomas Digges (1546–1595?) was the earliest Englishman to offer a defense of the Copernican theory. ... Accompanying Digges's account is a diagram of the universe portraying the heliocentric system surrounded by the orb of fixed stars, described by Digges as infinitely extended in all dimensions.
^Gilbert, William (1893). "Book 6, Chapter III".De Magnete. Translated by Mottelay, P. Fleury. (Facsimile). New York: Dover Publications.ISBN0-486-26761-X.{{cite book}}:ISBN / Date incompatibility (help)
^Taton, René; Wilson, Curtis (1989).Planetary astronomy from the Renaissance to the rise of astrophysics. Cambridge University Press.ISBN0-521-24254-1.OCLC769917781.
^Galileo Galilei,Sidereus Nuncius (Venice, (Italy): Thomas Baglioni, 1610),pages 15 and 16.Archived March 16, 2016, at theWayback MachineEnglish translation: Galileo Galilei with Edward Stafford Carlos, trans.,The Sidereal Messenger (London: Rivingtons, 1880),pages 42 and 43.Archived December 2, 2012, at theWayback Machine
^Alec EdenThe search for Christian Doppler, Springer-Verlag, Wien 1992. Contains a facsimile edition with anEnglish translation.
^Fizeau: "Acoustique et optique".Lecture,Société Philomathique de Paris, 29 December 1848. According to Becker(pg. 109), this was never published, but recounted by M. Moigno(1850): "Répertoire d'optique moderne" (in French), vol 3. pp 1165–1203 and later in full by Fizeau, "Des effets du mouvement sur le ton des vibrations sonores et sur la longeur d'onde des rayons de lumière"; [Paris, 1870].Annales de Chimie et de Physique, 19, 211–221.
^Pohle, J. (1913)."Angelo Secchi" . In Herbermann, Charles (ed.).Catholic Encyclopedia. New York: Robert Appleton Company.[...][his] theory of the unity of the world and of the identity of the fixed stars and the sun received most profound scientific demonstration and confirmation.
^England, P.; Molnar, P.; Righter, F. (January 2007). "John Perry's neglected critique of Kelvin's age for the Earth: A missed opportunity in geodynamics".GSA Today. Vol. 17, no. 1. pp. 4–9.doi:10.1130/GSAT01701A.1.
Bunch, Bryan, and Alexander Hellemans,The History of Science and Technology: A Browser's Guide to the Great Discoveries, Inventions, and the People Who Made Them from the Dawn of Time to Today.ISBN0-618-22123-9
P. de Bernardis et al., astro-ph/0004404, Nature 404 (2000) 955–959.
Laërtius, Diogenes."Others: Parmenides" .Lives of the Eminent Philosophers. Vol. 2:9. Translated byHicks, Robert Drew (Two volume ed.). Loeb Classical Library.